Chlorine induced degradation of SOFCS operating on carbon containing fuels

Abstract

Chlorine present in green and synthetic fuels such as biogas and syngas can accelerate degradation of solid oxide fuel cell (SOFC) nickel-based anodes. Chlorine contamination has been studied in SOFCs where H 2 was the primary fuel but little attention has focused on deleterious, cooperative effects that result from Cl-contamination in predominantly carbon-containing fuels. Experiments described in this work examine degradation mechanisms in SOFCs with Ni-YSZ cermet anodes operating with a biogas surrogate and exposed to 110 ppm Cl (delivered either as CH 3Cl or HCl). Operando Raman spectroscopy is used to directly observe the the anode's catalytic activity as evidenced by observable carbon accumulation, and electrochemical impedance and voltammetry measurements report on overall cell performance. Studies performed at 650 °C and 700 °C show that Cl suppresses carbon accumulation and causes slow but steady cell degradation. Prolonged exposure to Cl results in and irreversible device failure. These results differ markedly from recent reports of Cl contamination in SOFCs operating independently with H 2 and CH 4.